The invention relates to a torque transmission unit for the drive connection of at least one secondary unit with an internal combustion engine, comprising an input member for connection with an output shaft of the internal combustion engine, an output member for connection with the secondary unit, a planetary gear, a free-wheel and a clutch device for rotation-fast connection of a member of the planetary gear with a stationary support part or with another member of the planetary gear.
When there is mention of planetary gears, this term is to be understood in the broadest sense. The breadth of the term planetary gear appears from an article by Herbert W. Muller in the periodical ANTRIEBSTECHNIK 28 (1989), No. 4, page 57, where there is reference especially to the sketches of principles (a) to (g) therein. By planetary gear within the meaning of the invention there are understood all those gears in which it is possible by installation of a free-wheel between two gear parts and a clutch between two gear parts to achieve a variation of transmission ration between input part and output part simply in that the clutch is opened or closed according to choice. It is then not necessary that a hollow wheel be present in addition to a sun wheel, a cross-piece and a planet wheel. Rather the hollow wheel can be replaced by a further sun wheel. The planet wheel can be of single-stage or two-stage construction. If two sun wheels are used, the planet wheel can be made also as a bevel wheel which meshes at the same time with the two sun wheels-- likewise formed as bevel wheels.
The free-wheel does not necessarily need to be arranged between two rotating parts of the planetary gear, but can be arranged between a stationary support part and a rotating part of the planetary gear. Likewise the clutch device does not necessarily need to be arranged between a rotating part of the planetary gear and a stationary part; rather can it be arranged equally between two rotating parts of the planetary gear.
Examples of embodiments of planetary gears are also disclosed for example in Published German Application P 37 40 082.7 of the Applicants (publication date: Jun. 8, 1989), and in corresponding patent applications in
Great Britian 8,827,300.8; (abandoned) PA1 France 8,616,094 PA1 U.S. application Ser. No. 272,739; (abandoned) PA1 Italy 68,049-A/88. PA1 (a) a notification of the shortfall of a pre-determined first rotation rate of a rotating part of the planetary gerar is present and PA1 (b) a notification regarding a need for an increase of rotation rate is present from the secondary unit or a system supplied by the secondary unit. The additional condition (b) for a variation of the transmission ratio in the direction of an increase of the rotation rate of the output member is conducive to driving comfort: Then in fact the change of transmission ratio does not occur every time a pre-determined first rotation rate is understepped, but only when at the same time a notification is present as to the need for increase of rotation rate. The jolts on the internal combustion engine, to be expected due to engagement of a higher transmission ratio, are thus reduced in number. The driving comfort can be still further refined in that the transmission ratio between output member and input member is variable in the direction of an enlargement of the rotation rate of the output member, if in addition to the notifications (a) and (b) (c) at least one of the notifications according to (a) and (b) persists over a first pre-determined time. PA1 (d) a notification as to a pre-determined retardation of the rotation rate of a rotating part of the planetary gearing is present.